Postdoctoral Scholar in Sustainable Development

Tropict: A clearer depiction of the tropics

2016 January 15

Tropict is a set of python and R scripts that adjust the globe to make land masses in the tropics fill up more visual real estate. It does this by exploiting the ways continents naturally “fit into” each other, splicing out wide areas of empty ocean and nestling the continents closer together.

All Tropict scripts are designed to show the region between 30°S and 30°N. In an equirectangular projection, that looks like this:

It is almost impossible to see what is happening on land: the oceans dominate. By removing open ocean and applying the Gall-Peters projection, we get a clearer picture:

There’s even a nice spot for a legend in the lower-left! Whether for convenience or lack of time, the tools I’ve made to allow you to make these maps are divided between R and Python. Here’s a handy guide for which tool to use:

(1) Supported image formats are listed in the Pillow documentation.(2) A TSR file is a Tropict Shapefile Reinterpretation file, and includes the longitudinal shifts for each hemisphere.

Let’s say you find yourself with a NetCDF file in need of Tropiction, called bio-2.nc4. It’s already clipped to between 30°S and 30°N. The first step is to call splice_grid.py to create a Tropicted NetCDF:

python ../splice_grid.py subjects/bio-2.nc4 ../bio-2b.nc4

But that NetCDF doesn’t show country boundaries. To show country boundaries, you can follow the example for using draw_map.R:

James Rising, UC Berkeley

James Rising is a researcher at the Energy and Resources Group at UC Berkeley. He studies and develops frameworks to model the feedback loops between environmental and human systems. He hopes to use new technologies to help communities act on
those insights to mitigate climate change and promote social justice.

James previously taught assorted seminars at MIT's Experimental Study
Group and electrical engineering at Franklin W. Olin College of
Engineering. Until recently, he worked as a software developer,
working with over a dozen companies on signal processing, social
networks, and artificial intelligence projects.